1. Technical Field of the Invention
The present invention relates to novel cosmetic and/or therapeutic compositions for topical application to mammalian subjects which are intended to induce and stimulate hair growth and/or to slow down or retard hair loss.
2. Description of the Prior Art
In human subjects, hair growth and hair renewal are principally determined by the activity of the hair follicles. This activity is cyclic and essentially entails three phases, namely, the anagenic, catagenic and telogenic phases. The anagenic active phase, or growth phase, which lasts for several years and during which the hair elongates, is followed by a transitional catagenic phase of about two weeks, during which the follicle regresses and becomes involuted, after which there is a rest phase or telogenic phase which lasts about 70 days, at the end of which the hair falls out. Following this, another cycle begins. The follicles are genetically programmed to produce about 25 regrowths, and a normal cycle lasts on average for five years, thereby permitting permanent renewal of the head of hair during a lifetime. Out of the approximately 150,000 hairs which make up a head of hair, usually about 80 thus fall out each day, which will be replaced in a few months.
Early thinning of the head of hair, or alopecia, which occurs in certain individuals, has both genetic and hormonal implications. The genetic aspect is seen when it corresponds to the "bald nature" which is transmitted from father to son, and more rarely from mother to son, and is very probably carried by several genes. The hormonal aspect is seen when it is due to binding to molecular receptors in the root of certain enzymatic degradation products of testosterone, the principal male hormone, these aspects developing, for example, following stress. This results in an accumulation of collagen in the collective sheath (fibrosis), leading to a slowing-down in the growth of the hair, and later its death. The disturbances in hair renewal are reflected, in a first stage, by acceleration of the frequency of the cycles, at the expense of the quality of the hair and then of the amount thereof: there is gradual thinning of the head of hair by regression of the so-called "end" hairs at the duvet stage, and finally the moment is reached at which there is no further regrowth. In men, the areas affected are principally the temporal or frontal areas and the occipital region. In women, diffuse alopecia of the vertex is observed.
More than 11 million men in France alone are directly affected by hair loss. Thus, compounds and compositions which make it possible to eliminate or reduce the effect of alopecia, and especially of inducing or stimulating hair growth or of decreasing hair loss, have long been sought in the cosmetic and pharmaceutical industries.
In approaches featuring a carbohydrate base, the synergistic action of mono-, di- and oligosaccharides with various active agents has recently been described; for example fructose in combination with polyvinylpyrrolidone (see JP-08,040,846), trehalose with chitosan and various natural active agents (see JP-08,020,514), the hydrolysis products of alginic acid with a blood circulation accelerator and a cell activator (see WO-96/07393), starch in combination with zinc oxide and boric acid (see WO-95/35086), and glucose or fructose in combination with globular cereal proteins or hydrolyzates thereof (see FR-27/04751).
Oligosaccharides containing at least one disaccharide structural unit comprising a uronic residue and a hexosamine residue (see EP-211,610) have also been described.
Aldonolactones or hexosaccharic acids too have been described, for example D-fucono-1,5-lactone (see EP-531,111), lactam forms of saccharides, for example L-arabino-1,5-lactam and D-glucurono-6,3-lactam (see EP-0,334,586), a cellobione/lactone polymer obtained via its derivation into N-p-vinyl benzyl D-cellobionamide (see JP-05,043,418).
Glycosides of ergosterol (see JP-07,101,835 and JP-07,109,293), of stigmasterol (see JP-07,138,181), of stigmastanol (see JP-07,109,294) and p-.beta.-D-glucopyranosyloxycinnamic acid (see JP-07,258,042) or glucosides derived from saponins (see WO-94/06402) are also known to this art.
Only rarely do structures result from the grafting of an alkyl chain onto a polyol. However, monopentadecanoylglycerol (see Yokoyama Daisaburo, Yukagaku 1995, 44 (4) 266-73), polyalcohol glyceryl ethers, in particular those obtained by condensation of pentaerythritol with pentadecyl glycidyl ether (see JP-08,157,331) and, more particularly, for carbohydrate-derived structures, undecylenyl trehalose (see JP-08,053,326) and alkylpolyglycosides and/or O-acyl glucose derivatives (see WO-93/02657) corresponding to the structure: ##STR2## in which R.sub.1 is a radical or a mixture of alkyl or alkenyl radicals and/or has the structure: ##STR3## in which R.sub.2 is a linear hydrocarbon chain and R.sub.3 is hydrogen or a lower C.sub.1 -C.sub.4 alkyl group, have indeed been described. All of these structures, which are carbohydrate-based, differ from those of the invention, hereinbelow more fully described.
Minoxidil.RTM. and Aminexil.RTM. are also known agents for improving the condition of the hair. Minoxidil, or diamino-2,4-piperidono-6-pyrimidine-3-oxide and derivatives thereof (see U.S. Pat. Nos. 3,461,461, 3,973,061, 3,464,987 and 4,139,619), which are molecules initially known for their anti-hypertensive activity, have also proven to be active in the treatment of hair loss. They stimulate division of the cells which constitute the hair, promote vascularization of the root and, lastly, retard the fibrosis and atrophy of the hair root.
However, although Minoxidil.RTM. diminishes hair loss in one-third of patients and effects a slight amount of hair regrowth in another third, it remains ineffective on the other individuals treated. When applied morning and evening in the form of a lotion, it occasionally entails side effects, such as palpitations, a lowering of blood pressure or eczema. Moreover, the hair becomes greasy over the course of this generally permanent treatment.
Aminexil.RTM., which is similar in structure to Minoxidil.RTM. (see WO 96/09048), is diamino-2,4-pyrimidine-3-oxide, a molecule capable of combating the production of the principal enzyme responsible for fibrosis. However, this cosmetic compound unfortunately does not act on the other causes of alopecia, namely, the hormonal and vascular factors, which limits its field of application to a fraction of the individuals afflicted with alopecia.
Thus, serious need continues to exist in this art for yet other active compounds for stimulating/inducing hair growth and/or retarding hair loss.
In addition, compounds of the type 2,3-dihydroxypropyl-2-(1-oxoalkyl) amino-2-deoxyglucopyranoside have been formulated into washing compositions for the hair, in particular those having anti-dandruff and hair-conditioning properties (see FR-95/12215).